Function TestElectionFailover

tests/integration/v3_election_test.go:114–175

TestElectionFailover tests that an election will

(t *testing.T)

// TestElectionFailover tests that an election will
func TestElectionFailover(t *testing.T) {
	integration.BeforeTest(t)
	clus := integration.NewCluster(t, &integration.ClusterConfig{Size: 3})
	defer clus.Terminate(t)

	cctx, cancel := context.WithCancel(context.TODO())
	defer cancel()

	ss := make([]*concurrency.Session, 3)

	for i := 0; i < 3; i++ {
		var err error
		ss[i], err = concurrency.NewSession(clus.Client(i))
		if err != nil {
			t.Error(err)
		}
		defer ss[i].Orphan()
	}

	// first leader (elected)
	e := concurrency.NewElection(ss[0], "test-election")
	if err := e.Campaign(context.TODO(), "foo"); err != nil {
		t.Fatalf("failed volunteer (%v)", err)
	}

	// check first leader
	resp, ok := <-e.Observe(cctx)
	if !ok {
		t.Fatalf("could not wait for first election; channel closed")
	}
	s := string(resp.Kvs[0].Value)
	if s != "foo" {
		t.Fatalf("wrong election result. got %s, wanted foo", s)
	}

	// next leader
	electedErrC := make(chan error, 1)
	go func() {
		ee := concurrency.NewElection(ss[1], "test-election")
		eer := ee.Campaign(context.TODO(), "bar")
		electedErrC <- eer // If eer != nil, the test will fail by calling t.Fatal(eer)
	}()

	// invoke leader failover
	err := ss[0].Close()
	require.NoError(t, err)

	// check new leader
	e = concurrency.NewElection(ss[2], "test-election")
	resp, ok = <-e.Observe(cctx)
	if !ok {
		t.Fatalf("could not wait for second election; channel closed")
	}
	s = string(resp.Kvs[0].Value)
	if s != "bar" {
		t.Fatalf("wrong election result. got %s, wanted bar", s)
	}